宁永慧
,
郭永飞
,
马天波
,
薛旭成
液晶与显示
doi:10.3788/YJYXS20132806.0927
为了改善高分辨率TDICCD成像系统图像数据的高速传输特性,设计了FPGA内部实现5/3提升小波的动态RAM结构.该结构通过循环利用同一RAM资源进行图像数据的同时读写,解决了5/3提升小波在FPGA实现过程中的RAM不足问题,提高了RAM资源利用的有效性.试验表明,5/3提升小波在FPGA内部的动态RAM实现过程,具有实时性高、可靠性好、占用资源较小等优点.该方法在图像预压缩、图像去噪、图像实时传输等方面有重要的意义.5/3提升小波在FPGA中的动态实现,完成了5行数据存储的提升小波处理过程,增强了星上实时数据的处理能力,为后续程序的开发奠定了基础.
关键词:
动态RAM
,
5/3提升小波
,
FPGA
,
时间延迟积分CCD
孟新强
兵器材料科学与工程
doi:10.3969/j.issn.1004-244X.2000.04.004
雷达吸波材料(RAM)技术是隐身技术中的重要技术之一,并且在隐身武器,尤其是隐身飞行器系统设计中得到广泛应用.本文首先简要阐述了雷达吸波材料吸波的基本原理,然后以隐身导弹薄型弹翼的低雷达散射截面(RCS)设计为例,探讨了涂覆型雷达吸波材料涂覆方案的设计思杨和方法,最后给出一部分隐身飞行器薄型翼面低RCS设计的样例.
关键词:
隐身技术
,
RCS
,
RAM技术
,
隐身飞行器
,
薄型翼面
,
涂覆方案
H. Y. Zhao
,
A. L. Lu
,
Q. Y. Shi and F. Yan (Welding Division
,
Department of Mechanical Engineering
,
Tsinghua University
,
Beijing 100084
,
China)
金属学报(英文版)
T-joints are widely used in ship manufacturing and other welding structures.The welding residual stress and deformation hare significant influence on failure and service life in welding structures.By us- ing of 3D thermal elasto - plastic FEM, the temperature fields,stress fields and deformation of weld- ing processes on T - joints are analyzed in this paper.The moving heat source is considered in the com- putation. Moreover, weld metal filling and multiple - pass welding are simulated using activate/deac- tivate ability.For avoiding "locking" in full integration elements of welding computation,the re- duced intergration elements are used in weld area.The nonlinear FEM analysis program MARC is used to complete the computations, as well as its user subroutines that are programmed to develop the special techniques needed in the simulation of welding process.Some different welding procedures are com- pared, and the welding residual stress and deformation are discussed in details.
关键词:
welding
,
null
,
null
,
null
,
null
Chinese Physics Letters
The magnetic properties of 1 T-TaS2 and 1 T-Fe-0.07 Ta-0.93 S-2 have been studied, Experimental results show that the phase transition temperature of 1 T-TaS2 is a function of the magnetic field, At low temperatures, both compounds are in a mixed state of charge density wave -spin density wave due to the coherent superposition of antiferromagnetic coupling.
关键词:
density
李东风
,
王浩静
,
贺福
,
王心葵
新型炭材料
doi:10.3969/j.issn.1007-8827.2007.01.011
利用SEM、元素分析、XRD和激光Raman光谱研究了T300和T700的形貌、化学组成和微观结构参数.结果发现:T700炭纤维表面光滑,而T300炭纤维的表面有大量的沟槽.表明前者是用干喷湿纺原丝,后者是用湿法纺丝原丝.两种纤维的断面均呈现出颗粒状特征.T700的含碳量高于T300,含氮量低于T300.两者的微观结构参数(d002、La和Lc)差异佐证了T700的炭化温度高于T300.T700的择优取向角Z比T300小2.3°,是石墨微晶致密有序排列的反映,因而使其体密度比T300高2.27%,空隙率低7.54%.所以致密化赋予了T700较高的拉伸强度.
关键词:
PAN基炭纤维
,
微观结构
,
XRD
,
Raman光谱
